Computerized mapping systems are being developed in order to assist motorists in determining preferred routes in traveling between two or more locations. Examples of computerized mapping systems include: Map Quest™, Yahoo! Maps™, SMART pages™, AutoPilot™, and Rand McNally™. In addition to the above examples, Mercedes Benz and BMW have incorporated similar computerized mapping systems into their automobiles' on-board computer systems.
In general, computerized mapping systems function as follows. The operator enters a starting point and a destination. The computerized mapping system may access a map database containing road information. Each road in the database may be broken up into segments. The segments may begin and end at intersections, speed zones, or a change in the number of lanes. The information of a road segment in the map database may include: the length of the segment, speed limit, and which road segments connect to the endpoints of the segment. The mapping system may plot out a number of probable routes comprised of road segments connecting the starting point and the destination. An estimated travel time for each route may be calculated by summing the quotient of the distance traveled in a particular speed zone by the speed limit of the zone. A route may then be selected based on the shortest estimated time required to travel the route. The travel route may then be communicated to the operator.
If, however, an operator strays off-course from the designated selected route of travel, there is no way for the operator to become aware and make necessary course adjustments. Further, existing systems are frequently not up to date with regard to traffic delays which may be encountered while traveling the selected route. Further, this shortcoming results in mapping programs which provide incorrect information since traffic delays are not programmed into a calculation of the travel time to arrive at a designated destination. Instead, many current systems use the posted speed limit for travel segments in calculating travel time and traffic delays are not considered.
Thus there is a need for an improved methodology and implementing mapping system which provides more accurate information to a user regarding expected travel time, routing and on-course conditions of a vehicle in traveling between selected starting points and a destinations.